What is air pollution

Air Pollution

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What is air pollution

DEFINITION

   Pollution is an undesirable change in the physical, chemical and biological ch-

aracteristics of the air we breath, water we drink and land we live. It is the unf-

avourable alteration of the environment partly or completely as a byproduct of

man's activities through direct or indirect effects of change in energy patterns,ra-

diation levels, chemical and physical conditions and over production of or-

ganisms.

     Air pollution is considered to be the most common and dangerous type of

environmental pollution. Industrial and metropolitan cities like Delhi, Mumbai,

Calcutta, Madras, Bhopal, Hyderabad, Firozabad, London, Newyork, Tokyo etc. are mostly affected by air pollution. The first recordered event of air pollution was observed in the Meuse valley of Belgium in 1930. The Donora, Pennsylvania incident of killingsmog, 1948 was a dreadful instance of air pollution. Nearly 4500 people were died in London, 1952 due to "Deadlier smog" an example of air Pollution. According to Newell (1971) 164 million tons of pollutants enter the air of united states every year. (What is air pollution). The worst event of air pollution took place in Bhopal in 3rd December, 1984 due to leakage of MIC (methyl-iso-cyanata) a toxic gas from the Union Carbide Pesticide plant. More than 5000 people were killed and some 50,000 were seriously affected and many went blind.

AIR POLLUTANTS

       Air pollutants are generally found in gaseous forms as well as in the form of particles mixed with the gases of atmosphere. Some of the common poll-

tants are : 

1.   Carbon Dioxide: 

       Carbon dioxide  found in atmosphere in

        low concentrations (about 0.03%) and  

       helpful in photosynthesis of plants.

       However its higher concentration in 

       atmosphere causes adverse effects to 

       all the organisms. 

2.   Carbon Monoxide : 

      Carbon monoxide (CO) is a dangerous

      air pollutant. It is formed from the 

      incomplete combustion of carbon

      compounds. Automobiles release 

      carbon monoxide using fossil fuels,

      closed rooms with blocked furnace

      fires in homes, natural gases in closed

      areas etc. release carbon monoxide

      causing the death of several hundred

      people and animals each year. The

      toxic effects of. carbon monoxide on

      man and animals result due to its   

      reversible combination with hae-

      moglobin of the blood which lessens

      the oxygen carrying capacity of

      haemoglobin, plants are affected by  

      carbon monoxide at a higher

      concentration in atmosphere.

3.  Oxides of Sulphur: 

     Sulphur dioxide (SO2), sulphur trioxide

    (SO) are also causing air pollution.

    Sulphur oxides damage materials by

    their conversion to sulphuric acid.

    Marble, limestone, slate etc. are

    damaged due to the effect of sulphuric

    acid. The corrosion of metals like iron,

    zinc, copper etc. takes place by oxides

    of sulphur. Plant and animals including

    human beings are greatly affected due

    to air pollution caused by sulphur 

    oxides.

4. Hydrogen Sulphide:

     It is a colourless toxis gas with pungent

     odour. The gas is mostly released from

     decaying plant and animal materials.

     Sulphur springs, Volcanic discharges,

     coal peats, swampy vegetation rich

     areas are also the sources of hydrogen

     sulphide (H,S). Normally it does not

     cause serious problems as it gets

     oxidised to elemental sulphur and

     sulphur dioxide. It causes some

     pulmonary and respiratory disorders of

     human beings and other animals.

     Continuous exposure of plants to

     hydrogen sulphide checks the growth

     and damage the shoot system.

5. Nitrogen Oxides : 

    Nitric Oxide (NO) and nitrogen dioxide

   (NO) emitted to atmosphere cause air

    pollution. Nitrogen oxides are formed by

    the reactions of nitrogen with oxygen at

    high temperatures i.e. 1100°C and

    instant cooling. In urban areas the air is

   found with such oxides. All the organ-

   isms i.e. plants and animals are affected

    by such pollutants. Serious illness and

   death of human beings resultedexp-, 

   osing to nitrogen dioxide. Damage of

   lung, heart, liver, kidney etc. are noted in

   animals inhaling nitrogen oxide for an

   hour or so. (What is air pollution) 

6. Ammonia : 

    Plants exposed to a higherconcen-

    tration of ammonia are affected

    seriously both in root and shoot sy-

    stems. Atmospheric air is contaminated

    with ammonia due to manufacture of an

    hydrous ammonium fertilizers and nitric

    acids. Ammonia causes the reduction of

    root and shoot growth. Reduction in the

    germination rate of seeds, formation

    lenticles, development of abscision

    layers  on fruit plants are some of the

   disasters caused by ammonia.

7.   Hydrogen Chloride: 

      It is released out as a byproduct from

      different chemical manufacturing

      plants. Hydrogen chloride may also be

      released due to combustion of c-

      hlororinated hydro carbons, coal,

      petroleum etc. Vegetation is greatly

      affected by hydrogen chloride.

      Defoliation, chlorosis in plants are

      observed due to exposure to hydrogen 

      chloride.

8.   Hydrogen Fluoride: 

      This air pollutant is released from

      active volcanoes, different industries

      related to electro chemical reduction

      plants, fertilizer industries and also

      combustion of coal and petroleum

      products. Vegetation are greatly

     affected by it. The tips of leaves burn

     away, premature flower formation,

     parthenocarpy are some of the effects

     played by hydrogen fluorides.

9.    Photochemical Smog :

       In natural condition sometimes sun

       light  helps the reaction of oxygen with

       nitrogenous substances and h-

       drocarbons like methane, ethane and

       toluene to form intermediate radicals

       These radicals cause the generation of

       secondary pollutants like aldehyde,

       formaldehyde and peroxyacetyl nitrate

      (PAN) which are collectively form pho-

       tochemical Smog. These secondary

       pollutants are very much harmful for

       both flora and fauna. Animals including

       man face different problems related to

       their health. Plants suffer due to fall in

       photosynthesis and other biochemical

       activities.

10. Ozone: 

       Ozone is formed in the environment

       chemically by the action of ultraviolet

       light on nitrogen oxide. The nitric oxide

       can be oxidised to nitrogen dioxide, by

       atmospheric oxygen. Sunlight splits up

       nitrogen oxide again into nitric oxide

       and atomic oxygen. What is air      

       pollution. The released atomic oxygen  

       combines with at mosphic oxygen 

       converts into ozone.

       Ozone causes different problems.

       Coughing, headache, pulmonary

       congestion, haemorrhage etc. are

       common human diseases caused by

       the affect of ozone. Leaf burn, 

       tip-disorder, potato inflorescence

       burning etc. are related to the exposure

      of plants to ozone. Ozone concentration

      is found increasing in the atmosphere of

      big cities due to the effect of sunlight on

      various waste products of combination,

      causing health hazards and damage in

      crop production.

11. Tobacco Smoke : 

       Smoking of cigarettes, hookas, bidis

       etc. cause air pollution in closed

       atmospheres like trains, buses auditoria

       etc.What is air pollution Different types

       of respiratory and  pulmonary 

       disorders related to hear diseases of 

       man are caused by tobacco  smoke.

       Prolonged exposure of tobacco

       smoke also cause the formation of

       precursors for cancer in man. 12. Dust

       Particles : Dust also causes the air

       pollution. The particles can travel

       several thousand kilometers in the

       atmosphere crossing seas and deserts.

       Respiratory disorders are caused due to

       such pollutants. Cities and urbanized

       localities are found with more dust in

       the atmosphere. Industrial belts are

       mostly affected by dust particles,

13. Lead and Fluorides : 

      Automobile exhausts are the main

      sources of lead pollution of the air. Lead

     arsenate is used in the manufacture of

     insecticides in plastic industries too lead 

     is used a raw material. Point and col-

     ouring industries largely use lead in 

     theirm anufacturing process.Atmosphere

     is found to be contaminated by lead in

     these localities causing lead poison in

     animals and man. Vegetation is also

     heavily damaged due to this pollutant.

     Fluorides are released from the different

     industries as a byproduct. The fluorides

    cause abnormal calcification of bones

    and teeth resulting their damage. 

14. Agricultural Chemicals : 

      Unscaled applications of different

      chemicals to agricultural lands like

      pesticides, fungicides, herbicides,

      insecticides etc. also cause air

      pollution. Such pollutants cause variable

     hazards on vegetation as well as

     animals. 

15. Hydro-Carbons: 

      These pollutants are comprised of

      hydrogen and carbon Automobiles are

      the main sources of releasing

      hydrocarbons. Methane, benzopyrene

     and benzene some of the common

     hydrocarbons are formed due to the

     partial combustion of petroleum

     products mainly in two-stroke engines.

     Hydrocarbons cause lung cancer;

     irritation of eye, nose and throat in man

     besides causing various metabolic

     problems in plants and other animals.

16. Aerosol : 

      Particles with dimensions about 2Aº in

      liquid or solid form are commonly 

      found  in normal condition of the       

      atmosphere.

      These particles other than pure water

      are called aerosols. Volcanic emission,

      forest fire, sea spray etc. are some of

      the natural causes of aerosol formation. 

      Seinfeld (1986) pointed out that most of

      the particulate matters are added into

      the atmosphere due to human int-

      erference. He has categorised it into 4

      groups as 

      (i) industrial operation

      (ii) transport operation 

      (iii) agricultural operations 

      (iv) loading and transfer operation.

      Aerosols cause different respiratory and

      pulmonary disorders in man leading to

      cancer.

17. Toxic Substances : 

      Arsenic (ASO); 1, 4-dioxane   

     1,2-dibromoethane; chromium ch-

      loroform;  carbon tetra chloride; 

     asbestos; 1, 2 dichloroethane; nickel;

     vinyl chloride; nitrosoamines are some 

     oft he toxic substance contaminating 

     witha tmosphere cause severe pollution.

     International Agency for Research on

     Cancer (IARC) have included these toxic

     substance mostly as carcinogens. 

18. Air Craft Effect:

       Atmosphere of modern cities is

       affected by the pollutant emissions

       from air crafts. Carbon monoxide and

       hydrocarbons with negligible amount of

       other air pollutants are released from

       air crafts. The apolo lunar models

       observed releasing ammonian, carbon

       monoxide, oxides of nitrogen to the

       atmosphere while the engine is in

       operation.

Conclusion:

     We are polluting the air by many factories, industries, vehicles and volcanoes etc. We need to reduce the pollution of air for get better atmosphere or better clean oxygen. Here in this topic I explained about this to how we can polluting the air.